Yes I do get that feeling. I will listen carefully and make my excuses.

Your gut feeling is the only thing you really have to rely on. If something doesn't feel right don't second guess yourself. It only takes one "Oh it'll be fine" and you might wind up dead in the worst case scenario.

yes, there are some typical things that I guess we all know, that are a instant gtf off my phone scenario, only sometimes I am over cautious and probably miss out on some lovely clients, if I ignore my instincts, they turn out to be a no show or a complete tosser 

Have a look for a book called The Gift of Fear - it explains how our intuition works and helps you learn to listen to it better.

Do you get this creepy feeling when he says first few words?
Once I ignored it and accepted a booking, I got attacked...

Sorry to hear you got attacked! Luckily I've never been physically attacked whilst escorting (fingers crossed) although a few times on the verge of sexual abuse! Yes I can tell a lot by a voice, and if I sense anything I don't like the sound of I'm suddenly fully booked.

I ignored my gut feeling yesterday and the guy was a complete arrogant tosser, I'm so angry with myself. Never again will I ignore my feelings, he made me feel ashamed of myself for doing this job and he knew exactly what he was doing. Not sure he warrants a warning but I've been very upset over it.

Some I know I don't want to see based on the first thing they say (or sound like) but sometimes I'm not sure so I have learned how to string out the conversation a bit before commiting to being available to make sure.

 So if they just say are available at 3pm rather than saying yes immediately, say How long are you looking for? or ask them if they have anything in mind for your session and then if they sound creepy and you don't want to do it  then can say something like Oh I've just checked my diary totally forgot I had something on at 2.30 and I won't be free today.

I have sometimes used my 'instinct' wrongly as in decided immediately I didn't like him and have said I wasn't available and then they have carried on to sound lovely and polite and have had to backtrack and say Oh actually I am free!

I think you need more than one line to go on unless they are totally rude immediately.